The present invention relates to a seal arrangement, in particular a brush seal, for a turbine, in particular an aircraft gas turbine, with a sealing element and a sealing surface interacting with the sealing element, wherein the sealing element and the sealing surface are arranged concentrically with respect to each other, in particular concentrically around a machine axis of the turbine.
Hitherto known brush seals for turbines or turbomachines usually have radially arranged bristles and a horizontal (axis-parallel), cylindrical running surface (sealing surface) at a rotor. This makes it possible to compensate for axial movements with respect to one another and to compensate for small radial movements. Furthermore, brush seals in which the brush inner diameter prior to mounting is smaller than the outer diameter of the sealing surface are known. A pre-tensioning of the bristles in a mounted state of the brush seal results thereby; that is, the bristles are bent or curved on at least a part of their radial length due to the acting compressive forces. This has the drawback that the possible compensation of radial movements of the rotor is smaller. Furthermore, on account of the pre-tensioned bristles, there results a preferred direction of rotation of the rotor (operating rotational direction); that is, the pre-tensioned bristles are bent or inclined in the peripheral direction. A rotation of the rotor in the direction opposite to the operating direction is not allowed or is not possible, because the bristles of the seal, which are inclined in the operating direction of rotation, exert a blocking effect. If, nonetheless, the rotor is moved opposite to the operating direction of rotation, damage to the seal can result; in particular, parts of the brush seal can buckle, so that undesired gaps are formed between the bristles and the sealing effect is lost.